The invention relates to a relay, in particular for a starter of an internal combustion engine, according to the general class of the independent claim.
Relays for starters of internal combustion engines are made known in DE 411 72 42 C1, for instance. The known relay includes a relay coil with a solenoid armature that can be moved when full battery current flows to the relay coil. As a result of the movement of the solenoid armature in the coil, a plunger attached to the solenoid armature is pressed against an operating lever after completing free travel. A contact member connected with the operating lever is thereby pushed in a straight line until it stops against two mating contacts, and a switch of an electrical circuit of a starter motor is thereby closed.
This known relay has the disadvantage, among others, that the solenoid armature can be lost, which makes handling of the relay difficult when mounting it on the starter. A further disadvantage is that only one contact return spring releases the contact member from the mating contacts, and this is insufficient to open the electrical circuit of the starter motor when xe2x80x9ccontact weldingxe2x80x9d takes place under unfavorable conditions.
Using the relay according to the invention having the features of the independent claim, it is possible, on the one hand, to design the relay in such a manner that the solenoid armature cannot be lost and, on the other hand, that the kinetic energy of the solenoid armature can be utilized after the relay coil is switched off to open the switch of the electrical circuit of the starter motor. A coupling element is provided for this purpose that connects the operating lever and the solenoid armature with each other in a manner that allows them to slide with limits.
Advantageous further developments and improvements of the features indicated in the independent claim arise out of the provisions listed in the subclaims.
Using a contact member situated on an operating lever, it is possible for the contact member to come in contact with mating contacts of the relay when full battery current flows to the relay coil. In this manner it is possible, for instance, to close the starter motor electrical circuit and by the switching-on. So that the contact member opens the starter motor switch after the intended end of the starting procedure and, therefore, after full battery current stops flowing to the relay coil, the solenoid armature is acted upon by a reset force that acts against the engaging direction of the relay. The coupling element is arranged in such a way that the solenoid armature can slide with limits in the reset direction in front of the operating lever. It is thereby possible that the solenoid armature carries the operating lever along by way of the coupling element, thereby making it possible to open the starter motor switch, in particular under unfavorable conditions such as when contact welding occurs. The operating lever includes an exposed frontal area that serves as the stop for a plunger attached to a solenoid armature. It is therefore possible that, during the engaging procedure, the solenoid armature presses against the operating lever by way of the plunger and thereby presses the contact member against the mating contacts to close the starter motor switch. The coupling element partially surrounds both the operating lever and the plunger. This is an advantage in particular when the coupling element is connected with the operating lever by way of a snap-on connector, because the coupling element can then be pushed over the operating lever more easily. A simple and cost-effective variant of a connection between the coupling element of the operating lever and the plunger is given in that the coupling element surrounds the operating lever and the plunger in the shape of a sleeve. A sleeve-shaped coupling element is an advantage in particular when the coupling element is made of sheet metal shaped like a sleeve. This also makes it easy to push it over the operating lever and the plunger. The coupling element fits behind either a corresponding counter-projection on the plunger or a corresponding counter-projection on the solenoid armature by way of at least one projection. If the solenoid armature does not include a plunger, the only possibility is to provide a projection on the solenoid armature itself. If the solenoid armature includes a projection, however, it is an advantage to provide the projection on the plunger, because the coupling element is not designed too large. In a further variant, the coupling element is designed in such a way that the operating lever is guided in a passage through the solenoid armature. If the coupling element is developed in sections in such a way that it guides the operating lever in a passage through the solenoid armature, the collar that is created as a result or that is present can be used so that a spring element rests against it and a contact member presses into a position removed from the coupling element.